重复注解

用@Repeatable标记的注解可以在注解目标类型上重复添加该注解。

RepeatAnnotationTest.java

@Test("test1")
@Test("test2")
public class RepeatAnnotationTest {
    public static void main(String[] args) {
        Test[] tests = RepeatAnnotationTest.class.getAnnotationsByType(Test.class);
        assert tests.length == 2;

        Tests annotation = RepeatAnnotationTest.class.getAnnotation(Tests.class);
        assert annotation != null && annotation.value().length == 2;

        IntStream.range(0, 2)
            .forEach(it -> {
                assert tests[it].equals(annotation.value()[it]);
            });

        Test test = RepeatAnnotationTest.class.getAnnotation(Test.class);
        assert Objects.isNull(test);
    }
}

Test.java

@Repeatable(Tests.class)
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface Test {
    String value();
}

Tests.java

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Tests {
    Test[] value();
}